In Star Wars, C-3PO is introduced to the audience when he and R2-D2 are aboard the consular ship Tantive IV when it is attacked by the ImperialStar DestroyerDevastator. When R2-D2 attempts to leave the ship to deliver a secret message to Obi-Wan Kenobi, C-3PO follows R2-D2 into an escape pod, which lands on the planet Tatooine. There, C-3PO and R2-D2 are captured by Jawas, and are taken to be sold. In the process of being sold to Owen Lars, C-3PO convinces his new owner to buy R2-D2 as well. The duo ultimately lead Lars' nephew, Luke Skywalker, to Obi-Wan, for whom R2-D2 plays Leia's message. After Imperial stormtroopers destroy the Lars homestead, C-3PO and R2-D2 go along with Luke and Obi-Wan on a mission to rescue Leia, transported by Han Solo and Chewbacca onboard the Millennium Falcon. When the ship is taken hostage on the Death Star, C-3PO helps R2-D2 shut down space station's trash computer, saving their human companions' lives, before escaping onboard the Falcon. When R2-D2 is damaged during the Battle of Yavin, a grief-stricken C-3PO offers to donate his spare parts to help repair his counterpart. C-3PO and a repaired R2-D2 are present at the celebration of the Death Star's destruction at the end of the film.

Throughout the film C-3PO is a foil to R2-D2's antics,[1] even when C-3PO translates R2-D2's machine speech for the audience. C-3PO was the property of the captain on the Tantive IV, but seems to follow R2-D2 in a relationship akin to those between human children;[HerzheldFP 1] C-3PO often following R2-D2 around, and R2-D2 needing C-3PO to translate for him.[HerzheldFP 2] When R2 is damaged in the Battle of Yavin, C-3PO offers to donate any mechanical parts helpful in his repair; but this transference is never confirmed.[2]

C-3PO also displays the ability to deceive humans (essentially favouring one human group over another).[3]

In The Empire Strikes Back, C-3PO is responsible for identifying the Empire's probe droid, alerting the Rebels to the Empire's awareness of their location on the 6th planet of the Hoth System. C-3PO escapes with Han, Chewbacca, and Leia in the Millennium Falcon, while R2-D2 joins Luke in his search for Yoda. During this time C-3PO and Solo are often shown as foils; C-3PO quoting odds and Han defying them. After a chase through the Hoth asteroid field, the Falcon escapes to Cloud City on Bespin.

While exploring a room in Cloud City, C-3PO is blasted by an off-camera stormtrooper. In search of R2-D2, Chewbacca heads to the Ugnaught recycling facility where he finds the dismembered parts of the droid. When Darth Vader reveals his presence to the group that same day, Chewbacca is sent into a holding cell, but is permitted to rebuild the droid, which he does poorly. Thereafter, Chewbacca carries the partially rebuilt C-3PO on his back during Han's encasement in carbonite.

With the help of the city's administrator, Lando Calrissian, Princess Leia, Chewbacca, and C-3PO escape the city. Having C-3PO on Chewbacca's back proves to be beneficial, in that when Boba Fett escapes the city with Han Solo, C-3PO notifies them of pursuing stormtroopers. While escaping Vader's flagship Executor, R2-D2 begins repairing C-3PO. After making their way to the Rebel's rendezvous point, C-3PO is fully repaired.

In Return of the Jedi, Luke commands C-3PO and R2-D2 to deliver a message to Jabba the Hutt, whereby C-3PO is used as Jabba's translator while R2-D2 serves on his flying sail barge. C-3PO's first translation for the crime lord is of the bounty hunter Boushh — Leia in disguise — claiming the bounty for Chewbacca.[4] Later, Luke infiltrates the palace and kills Jabba's rancor in a duel; whereupon Jabba transfers his court to the sail barge with Luke, Han, and Chewbacca as food for the Sarlacc, while Leia serves as Jabba's slave. When Luke attempts escape, R2-D2 tosses him his lightsaber, with which he attacks Jabba's guards. In the midst of the battle, C-3PO is attacked by Salacious Crumb, who pulls out his right photoreceptor before being driven off by R2-D2. Thereafter the two escape the sail barge and are retrieved by the protagonists.

C-3PO accompanies the strike force to the Forest Moon of Endor to disable the shield generator protecting the second Death Star. When he, Han, Luke, Chewbacca, and R2-D2 are captured by the Ewoks, C-3PO is perceived to be a god by the latter. When the human prisoners are threatened by the Ewoks, Luke levitates the droid above the crowd as demonstration of the supposed god's ability, so as to prompt release.[4] Later that night, C-3PO narrates the history and intentions of the Rebels to the tribe, convincing them to help the Rebels at the Battle of Endor. After the Empire's second Death Star is destroyed, C-3PO joins the protagonists on Endor in celebrating the fall of the Empire.

Shortly afterwards, C-3PO becomes part of Anakin's pit crew during the race, where he sees Anakin defeat Sebulba. C-3PO and Anakin part ways when Qui-Gon frees the boy after winning a bet with Anakin's master, Watto. Before parting from C-3PO, Anakin assures the droid that his mother Shmi will not sell him.[5]

In Star Wars: Episode II – Attack of the Clones, set 10 years later, Shmi is kidnapped by a group of Tusken Raiders. Sensing that his mother is in danger, Anakin travels with Padmé to Tatooine, where they reunite with C-3PO, now with a full body. He recognizes Anakin and Padmé instantly and presents them to Anakin's stepfamily Owen and Cliegg Lars and Beru Whitseun. When Anakin returns with his mother's body, C-3PO attends her funeral.

After Anakin and Padmé's visit to Tatooine, C-3PO accompanies them to the planet Geonosis to rescue Obi-Wan Kenobi. Shortly afterward, he follows R2-D2 into a droid-construction site, where his head is temporarily attached to the torso of a battle droid, while the head of the droid is placed onto C-3PO's torso. Influenced by the battle droid's programming, he reluctantly participates in the film's climactic battle scene, where he is stopped by Kit Fisto. Having been restored by R2-D2, he leaves Geonosis with the other protagonists. At the end of the film, he is a witness to Padmé and Anakin's marriage on Naboo.

In Star Wars: Episode III – Revenge of the Sith, C-3PO is aware of Padmé's pregnancy and the meetings held with Bail Organa and Mon Mothma. After Anakin and R2-D2 return from Anakin's massacre of the Jedi, C-3PO and R2-D2 conclude that the latter was the result of emotional pressure on Anakin.[6] C-3PO becomes a witness to his maker's turn to the dark side of the Force when he accompanies Padmé to Mustafar, and Anakin, now the Sith LordDarth Vader, uses the Force to choke her into unconsciousness; whereupon C-3PO and R2-D2 take her to safety. When Obi-Wan returns to their spaceship, C-3PO pilots it to Polis Massa and witnesses Padmé give birth to the Skywalker twins, Luke and Leia, and die shortly afterward. C-3PO and R2-D2 fall into the custody of Bail Organa, who orders that C-3PO's memories be erased to protect the twins from their father.[6]

Anthony Daniels again reprised the role of C-3PO in Star Wars: The Force Awakens, the first installment of the sequel trilogy, which was released on December 18, 2015. The film takes place thirty years after the events of Return of the Jedi and reunites many of the main cast from the original trilogy. Daniels has also signed to appear in the trilogy's two sequels. C-3PO is seen with a red painted left arm but gets a gold arm in the end of the film. In the film, he is first seen in the Resistance base with Leia, who is trying to look for Luke, who went into exile years before. C-3PO is a spymaster of the Resistance's network of spy droids, and is helping the Resistance in trying to find the droid BB-8. Later, he, along with Leia and a Resistance team, pick up Han, the stormtrooper Finn, BB-8, and Chewbacca on the planet Takodana. During their adventures, C-3PO is reunited with R2-D2, who is reactivated after having been shut off for decades.

With the 2012 acquisition of Lucasfilm by The Walt Disney Company, most of the licensed Star Wars novels and comics produced since the originating 1977 film Star Wars were rebranded as Star Wars Legends and declared non-canon to the franchise in April 2014.[7][8][9]

Before the release of The Phantom Menace and the revelation that C-3PO was constructed by a young Anakin Skywalker, the canon account of C-3PO's creation placed his construction on the planet Affa 112 years before A New Hope. This older version of his creation originated with George Lucas, and both versions were harmonized from the outset: in 1977, Lucas provided a guide for early Expanded Universe creators, in which C-3PO's origin on Affa was established, and also the statement that he was "totally reassembled by a young boy working for a junk dealer" before joining the Alderaanian diplomatic corps "several years" later. Some of the early material in this guide has since been superseded, but the two explanations remain generally compatible.

In all Star Wars media involving the Clone Wars, C-3PO serves as Padmé Amidala's personal protocol droid. In "The New Face of War", a story in Star Wars: Republic, Queen Jamillia appoints the droid to serve as liaison to the Jedi during that campaign following the defense of Naboo and the bio-plague of Ohma-D'un by the Separatists.[10] He is a reluctant participant in many of Padmé's adventures, including a hazardous mission during the Battle of Ilum,[11] in which his loyalty is essential in helping Jedi Master Yoda rescue fellow Jedi Luminara Unduli and Barriss Offee.[12]

In Clone Wars, C-3PO's outer plating are upgraded to a shiny bronzium coating due to his tenure as Padmé's servant.[13] He also severely disapproves of combat droids, once demanding to "have a serious talk with their programmer".[14]

During the Droids series, set between Revenge of the Sith and A New Hope, C-3PO and R2-D2 are traded to various masters. Highlights include an early encounter with bounty hunterBoba Fett,[15] and a change in personality brought by remodeling.[16]

In the Expanded Universe material set after Return of the Jedi, C-3PO assists Leia Organa, Luke Skywalker, and their allies in the Alliance (and later, the New Republic) on many missions. Due to his function as a protocol droid, he most often stays with Leia Organa-Solo on Coruscant, assisting her political duties, while R2-D2 often stays with Luke Skywalker at the Jedi Academy.

In The Truce at Bakura, he translates Ssi-ruuvi, the language of the Ssi-ruuk, to aid the Alliance.[17] In The Glove of Darth Vader, C-3PO and R2-D2 are members of the Senate Planetary Intelligence Network (SPIN), and undergo transformation by the Droid Modification Team to be disguised as Kessel droids so that they could infiltrate a gathering of Imperials to find out who is planning to take control of the Empire.[18]

In The Courtship of Princess Leia, C-3PO is led to believe that Han Solo is ancestrally the King of Corellia during Solo's competition with Prince Isolder for Leia's hand in marriage. Threepio agrees to assist Solo as a counselor droid; but is shocked when Solo kidnaps the princess and takes her to Dathomir. Despite this, Threepio continues to present Han in the best possible light and writes a song for him entitled "The Virtues of King Han Solo", which he backs with the sound of a full symphony orchestra. He later discovers that Solo's ancestor was merely "a pretender to the throne", but is present at Han and Leia's wedding.[19]

In Tatooine Ghost, C-3PO returns to Tatooine, where he helps Han and Leia in their search for an Alderaanian moss painting storing a valuable code. Here, he reunites with Kitster Banai and Wald, childhood friends of Anakin Skywalker. With their help C-3PO and the others discover Shmi's diary, whereof Leia remarks that the droid described reminds her of C-3PO. The code is eventually found and destroyed.[20]

In Dark Force Rising, C-3PO goes to Honoghr with Leia during the Thrawn Crisis to discover what had caused the plight of the Noghri. He is forced to hide with Leia and Chewbacca when Imperial forces arrive overhead,[21] but he later returns with Leia to Coruscant, where she gives birth to Jaina and Jacen Solo. He serves as caretaker to the twins, and later Anakin Solo as well. In Heir to the Empire, Lando reprograms C-3PO to sound like Leia in order to hide from Imperials on Nkllon; but the Empire, led by Grand Admiral Thrawn, sees through the deception. C-3PO also accompanies Han, Lando, R2-D2, Luke, Chewbacca, and Mara Jade to Wayland on a mission to destroy the Mount Tantiss storehouse. Thanks to C-3PO and some Noghri, the party recruits aid from the local population and destroys the storehouse.[22]

In Dark Apprentice, the Solo twins escape from Chewbacca's and C-3PO's watch during a trip to a zoo on Coruscant and arrive in the planet's sub-levels. C-3PO frantically searches for them, but they had been found by King Onibald Daykim and are reunited with their parents.[23]

In Empire's End, C-3PO and R2-D2 are nearly destroyed after they spot an Imperial installing a homing beacon on the Millennium Falcon; but are saved by Han Solo and Chewbacca. The resurrected Palpatine and his fleet discover the Alliance's existence, leading C-3PO and the others to flee to Iziz, a city on the planet of Onderon. Palpatine eventually finds them, but is wounded by Solo and destroyed when Empatojayos Brand sacrifices himself to save the latter's son Anakin.[24]

In Planet of Twilight, C-3PO and R2-D2 accompany Leia on a diplomatic mission to Nam Chorios but are unable to prevent her kidnapping and fail to stop the Death Seed plague unleashed on the crew by Seti Ashgad and Dzym. Eventually rescued by Han and Lando, the two droids convey their message for help.[25]

In The Crystal Star, C-3PO accompanies Luke Skywalker and Han Solo to Crseih Station to investigate the possible existence of Jedi trainees; but instead find Waru, a creature from another dimension, from whom they learn of Waru's alliance with Lord Hethrir and of the kidnapping of the Solo children. Hethrir is destroyed following a confrontation with Leia, Han, and Luke while Waru returns to his dimension.[26]

In The New Rebellion, C-3PO, along with R2-D2 and a young mechanic named Cole Fardreamer, is instrumental in stopping Kueller from regaining power by disabling the explosive devices he had placed in a large number of droids.[28]

In Ambush at Corellia, during the outbreak of the First Corellian Insurrection, C-3PO and Chewbacca retrieve Jaina, Jacen, and Anakin from the burning Corona House.[29] In Showdown at Centerpoint, Threepio accompanies Luke, Gaeriel Captison, Belindi Kalenda, and Lando Calrissian to Centerpoint Station, and alerts them to the fact that the temperature inside Hollowtown is increasing to dangerously high levels.[30] In Vision of the Future, C-3PO participates in Talon Karrde's expedition to the Kathol Sector to find Jorj Car'das, serving as a translator.[31]

In the ambiguously canon Star Wars Tales story Storyteller, C-3PO is found partially destroyed and abandoned, years after the events of the original trilogy, by two slave boys. He tells them stories of Luke Skywalker's adventures, and they imagine the stories played out by members of their own alien race. As he is finishing his tale, a Vindar slavedriver appears, blasts C-3PO's head off, and kills Otalp. After the Vindar leave the cave, Remoh finds a lightsaber in the remains of C-3PO's body and in so doing, finds hope for his people's freedom.

C-3PO was played by Anthony Daniels in all seven Star Wars films. In Episode I, a skeletal C-3PO model was puppeteered, with Anthony Daniels providing the voice, and the puppeteer was removed in post-production. For Episode II, Daniels requested to take over the puppeteering duties, but these scenes were later deleted. In Episodes III to VII, Daniels both wore the costume and provided the voice.

Daniels reprised his role of C-3PO for the Disneyland ride Star Tours, co-created by George Lucas in 1987. He was videotaped while recording the dialogue, with the tape serving as a reference for the Imagineers to program an audio-animatronic C-3PO in the queue area. Both it and the audio-animatronic R2-D2 are the original props used in filming. Daniels also donned the costume for certain video segments played before and after the simulator ride itself, also portraying an electronically disguised Ewok announcer. Daniels also appeared in the C-3PO costume for various promotional materials for Star Tours, including the electronic press kit, a Disney special on Star Tours hosted by Gil Gerard, and various opening day skits. When Star Tours opened a bilingual version at Disneyland Paris, Daniels re-recorded C-3PO's dialogue in French. C-3PO ends up in the pilot's seat of the Starspeeder 1000 in the attraction's successor, Star Tours–The Adventures Continue, and as a central character in the animated special Star Wars: The Padawan Menace. In these appearances, he is also played by Anthony Daniels.

Daniels made several appearances as C-3PO on numerous TV shows and commercials, notably on a Star Wars-themed episode of The Donny and Marie Show in 1977, Disneyland's 35th Anniversary and a Star Wars-themed episode of The Muppet Show in 1980. He also has a role as the character on Sesame Street episodes 1364 and 1396 (along with R2-D2).

The cover photo of the August 2015 issue of GQ featured comedian Amy Schumer wearing a replica of Princess Leia's bikini and sucking one of C-3PO's fingers. Lucasfilm and Disney objected to this image and released a public statement that it was unauthorized.[33]

The United States Navy built a robot in 2012 called the Autonomous Shipboard Humanoid which they claim was modeled on C-3PO. The robot was built for the purpose of extinguishing fires, but has similar movement abilities to the Star Wars droid by being able to climb ladders and carry hoses. Also similar to C-3PO, it can respond to human gestures, but at a much more basic level, unlike the Star Wars droid.[34][35]